1. Field of the Invention
The instant disclosure relates to a low noise amplifier; in particular, to a low noise amplifier that can dynamically adjust the bias point.
2. Description of Related Art
The wireless communication has developed dramatically. Nowadays, there are over 1 billion wireless mobile devices in the world. There are many bandwidths and communication protocols for mobile network, wide area network (WAN), local area network (LAN), public safety communication and military communication, which is hard to have the best implementation.
The Low Noise Amplifier (LNA) is generally used in the communication system, which is used for amplifying weak input signal received from antenna to be a signal with low noise. Moreover, the Low Noise Amplifier (LNA) is often configured at the front end of a communication system. Generally speaking, the Low Noise Amplifier (LNA) can reduce most of the noise and amplify the desired signals with frequencies near a center frequency. Therefore, it not only can increase the Signal-to-Noise Ratio (SNR) of the communication system, but also can increase quality of signal receiving. In the prior art, in conjunction with FIG. 1 and FIG. 2, FIG. 1 shows a circuit diagram of a traditional low noise amplifier and FIG. 2 shows a simulation waveform of a traditional low noise amplifier. When input power of the RF input signal increases, power gain of the traditional LNA may decrease from −25 dBm, and 1 dB gain compression point thereof is −15.5 dBm.